Hydroponic pH Controller: Automatic Nutrient Dosing

pH in hydroponic nutrient solutions is the most important factor for plant health. Outside 5.5-6.5, nutrient lockout occurs regardless of concentration. Automatic pH control maintains perfect conditions 24/7.

pH Control in Hydroponics

At pH 5.8-6.2, all 16 essential nutrients are maximally available. Above 7.0: iron, manganese, phosphorus lock out. Below 5.0: calcium and magnesium drop. Indian tap water pH 7.5-8.5 needs significant adjustment.

Sensor Requirements

Analogue pH probe (Rs 500-1,500) for real-time readings. DS18B20 in nutrient solution for temperature compensation (0.003 pH units per degree C). DHT22 for ambient conditions affecting transpiration and nutrient concentration.

Automatic Dosing System

Peristaltic pumps add pH-up (KOH) or pH-down (H3PO4) when pH drifts outside target. Arduino reads pH sensor, calculates adjustment, runs appropriate pump for calibrated duration.

Nutrient Management

EC monitoring tracks nutrient concentration. Water temp 18-22C optimal for roots. DS18B20 serves double duty: pH compensation + root zone monitoring.

Calibration

Calibrate weekly with pH 4.01 and 7.01 buffers (Rs 100-200/set). Store probe in KCl solution. Never let probe dry out.

Cost-Effective Hydroponics

Basic NFT system with auto pH/climate control produces 50-80kg lettuce/month in 100 sqft, generating Rs 8,000-12,000. Sensor system Rs 5,000-8,000 pays for itself month one.

Frequently Asked Questions

Calibration frequency?

Weekly with pH 4.01 and 7.01 buffers.

Best pH for leafy greens?

5.5-6.5, sweet spot 5.8-6.2.

Lemon juice for pH?

No. Unstable organic acid causes fluctuations. Use phosphoric acid.

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